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Streaming and Compressing Backups
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Streaming mode, supported by |Percona XtraBackup|, sends backup to ``STDOUT`` in special ``tar`` or |xbstream| format instead of copying files to the backup directory.
This allows you to use other programs to filter the output of the backup, providing greater flexibility for storage of the backup. For example, compression is achieved by piping the output to a compression utility. One of the benefits of streaming backups and using Unix pipes is that the backups can be automatically encrypted.
To use the streaming feature, you must use the :option:`--stream`, providing the format of the stream (``tar`` or ``xbstream`` ) and where to store the temporary files::
$ innobackupex --stream=tar /tmp
|innobackupex| starts |xtrabackup| in :option:`--log-stream` mode in a child process, and redirects its log to a temporary file. It then uses |xbstream| to stream all of the data files to ``STDOUT``, in a special ``xbstream`` format. See :doc:`../xbstream/xbstream` for details. After it finishes streaming all of the data files to ``STDOUT``, it stops xtrabackup and streams the saved log file too.
When compression is enabled, |xtrabackup| compresses all output data, except the meta and non-InnoDB files which are not compressed, using the specified compression algorithm. The only currently supported algorithm is ``quicklz``. The resulting files have the qpress archive format, i.e. every \*.qp file produced by xtrabackup is essentially a one-file qpress archive and can be extracted and uncompressed by the `qpress file archiver `_ which is available from :ref:`Percona Software repositories `.
Using |xbstream| as a stream option, backups can be copied and compressed in parallel which can significantly speed up the backup process. In case backups were both compressed and encrypted, they'll need to decrypted first in order to be uncompressed.
Examples using xbstream
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Store the complete backup directly to a single file: ::
$ innobackupex --stream=xbstream /root/backup/ > /root/backup/backup.xbstream
To stream and compress the backup: ::
$ innobackupex --stream=xbstream --compress /root/backup/ > /root/backup/backup.xbstream
To unpack the backup to the /root/backup/ directory: ::
$ xbstream -x < backup.xbstream -C /root/backup/
To send the compressed backup to another host and unpack it: ::
$ innobackupex --compress --stream=xbstream /root/backup/ | ssh user@otherhost "xbstream -x -C /root/backup/"
Examples using tar
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Store the complete backup directly to a tar archive: ::
$ innobackupex --stream=tar /root/backup/ > /root/backup/out.tar
To send the tar archive to another host: ::
$ innobackupex --stream=tar ./ | ssh user@destination \ "cat - > /data/backups/backup.tar"
.. warning:: To extract |Percona XtraBackup|'s archive you **must** use |tar| with ``-i`` option::
$ tar -xizf backup.tar.gz
Compress with your preferred compression tool: ::
$ innobackupex --stream=tar ./ | gzip - > backup.tar.gz
$ innobackupex --stream=tar ./ | bzip2 - > backup.tar.bz2
Note that the streamed backup will need to be prepared before restoration. Streaming mode does not prepare the backup.